| 项目编号: | 1345087
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| 项目名称: | Experimental simulation of earthquake rupture processes |
| 作者: | Ze'; ev Reches
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| 承担单位: | University of Oklahoma Norman Campus
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| 批准年: | 2013
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| 开始日期: | 2014-08-01
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| 结束日期: | 2018-07-31
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| 资助金额: | USD250000
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Earth Sciences
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| 英文关键词: | fault
; earthquake
; earthquake rupture
; natural earthquake
; complex process
; earthquake process
; san francisco earthquake
; earth crust rupture
; slip-velocity
; transient earthquake loading
; small earthquake
; earthquake loading
; earthquake laboratory
; constitutive relation
; actual earthquake
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| 英文摘要: | An earthquake occurs when a fault in the earth crust ruptures abruptly. The rock blocks that bound the fault, slip for tiny distance in small earthquakes, and up to a few meters in large events. During this slip, the fault weakens and the weakening provides energy to continue the earthquake rupture. Obviously, this is a complex process in which the mechanical properties of the fault drastically change within seconds. Classical experimental approaches to explore these processes are conducted at constant velocity or at very slow velocity; neither of these conditions is relevant to the rupture of natural earthquakes. We propose a new experimental approach that is anticipated to reveal key parameters that are relevant to earthquakes. These experiments will utilize the unique capabilities of energy supply and power control of our earthquake laboratory in the University of Oklahoma. The impact of these capacities was demonstrated in the preliminary work that succeeded in simulations of fault behavior during earthquakes up to magnitude M=8 (similar to 1906 San Francisco earthquake). Why are such experiments important? First, in general, better understanding of earthquake processes is essential for the reduction of seismic hazard. Second, this study is particularly important for the calculations of seismic ground shaking, which are used for building structural design. These calculations are based on the mechanical behavior of faults during earthquakes, and more accurate and relevant calculations require better knowledge of this behavior.
Theoretical models suggest that earthquake rupture is a complex process with non-trivial evolution of kinematic and dynamic properties (e.g., Tinti et al. 2005). Recent experiments that simulated the velocity history of actual earthquakes (e.g., Sone and Shimamoto, 2009; Fukuyama and Mizoguchi, 2010; Liao, Chang and Reches, in revision for EPSL) show that constitutive relations which were determined in low-velocity, short-distance friction experiments do not necessarily hold for variable, high slip-velocity of natural earthquakes. The present objective is to simulate the earthquake rupture process by loading experimental faults similarly to earthquake loading, and to derive the constitutive relation at these conditions. The experiments will be conducted with a high-speed rotary shear apparatus that applies frictional sliding along rock blocks under slip-velocity up to 1 m/s, normal stress up to 30 MPa, and large slip distance. This apparatus has two unique capabilities: (1) Loading the experimental fault by a finite amount of energy (up to 10^7 J/m^2) that is stored in a flywheel (Chang et al., 2012); and (2) A real-time feedback system that controls the power-density applied on the fault (power-density = slip velocity * shear-stress). These methods allow the application of any loading history to reveal the fault response under transient earthquake loading. The preliminary results of both methods show strong similarities to theoretical models of fault behavior in terms of the evolution of fault strength (weakening and strengthening), slip velocity, energy dissipation, and rise-time. We will link the observed constitutive relations to the mechanisms of fault weakening, and for this purpose, we will characterize the fault properties with ultramicroscopic methods (AFM, XRD, SEM, and TEM). |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/96220
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Ze',ev Reches. Experimental simulation of earthquake rupture processes. 2013-01-01.
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